To add a contact to your favorites, go to your contacts page > hamburger symbol in the top corner > Select “Add to favorites”. These contacts will then have a yellow star highlighted on them and remain pinned to the top of your address book.
The order of favorites is determined by the order you choose them. You can reorganize this list by Going to Home > Favorites > Hamburger symbol > Organize Favorites.
Then the Contacts will wiggle, and you can reorganize them as you would like.